Resiliently impelled speed responsive switch



United States PatentO RESILIENTLY IMTEELED SPEEDRESPONSIVE SWITCH.

James K Gaylord andrBewis-Et Thatcher, Ghicago, Illa; assignors to Gaylord-=Prodi1cts, Incorporated; Chicago,-

Illt, a corporation ofiDelaware ApplicationiNovember26;;1952 SeriaLNm 3.22am

aimSa (CL; EHO).

This; invention relates to irnprovements in a rotary speedresponsive" electric switch' and refers particularly to an electricswitchwhich, in response to a' predetermined rotary" speed oi a' body; will break-a main orrelaycircuit to produce a-signal;control a predeterminedoperation or the like;

Devices have heretofore been proposedifor making'or' liquid and'phaving atits bottom a metal plate. A'rotating body' is positi'onedabove the pool and carries one or more cantilever or blade springs, which, when the body is stationary. or moving. at a relatively low speed, dip into the pool'and make electrical'contact with the, metal plate.

Depending upon the strength or resiliency of, the spring member or memb he. efiec ingr ction.Qfl heliquid; upon the spring member or member can be madeto cause said members to. break contact. with said plate when the body reaches a predetermined rotary speed; The spring member onmembers, together. withthe plate may comprise. the switch points or electrodes of an electric switch connected in a suitable control, or signahcireuit to,be: actuatedor' deactuated'when the body reaches said predetermined rotary speed;

' Other objects" and" advantag s; ofthiei present invention will-be apparent from'th'e' accompanying drawing and following detailed description.

In the drawing, Fig. l is a sectional elevation of the r device comprising the present invention.

Fig. 2 is a transverse sectional view taken on line 22 of Fig. 1.

Referring in detail to the drawing, the device comprising the invention may include a housing 1 which may be cored or bored to provide a central cylindrical recess 2, a transverse recess 3, a lateral recess 4 and a bottom recess 5. The transverse recess 3, at one end may open into the lateral recess 4 and at the opposite end may open to one lateral side of the housing 1. The recess 2 and recess 3 may intersect in the body of the housing 1 and a continuation 6 of the recess 2 may open into the bottom recess 5.

A bearing 7 is positioned at the end of recess 3 and functions as a bearing for a shaft 8 which may be positioned in the recess 3. A closure member 9 may be positioned over the mouth of the lateral recess 4 and may cgrry a bearing ring 10 adapted for the support of sha t The present invention is adapted to function as a detector of rotary speed, being adapted to complete or break an electric circuit to produce an audible or visual signal or to start or stop a predetermined operation. The rate of rotation of shaft 8 may be proportional to the rate of rotation of some related machine or body or may be proportional to the translatory or rectilinear speed of a machine or body wherein a predetermined function, operation or signal is to be produced when the rotating body or the rectilinearly moving body reaches a predetermined velocity. Of course, the means for rotating the shaft 8 is] not shown; but: its is understood-abet theshafh will betoper -atively connected; tobanyndevice. whose:.oppra-s. tion is to I be controllpdsor aboutswhich a given. ,speedriofirotationor travel'iis totbemoted,

A cylindrical; member: 11-: is .fixedlypositionediin th'e recesses 2 and 6, said cylindrical member being pravideda with a. transverse bore -;-12 :for theneception; of. shaft -8. At the loweri end;qfrthetcylindrieal:membenim a.re-.

stricted portion. .1-'3",-'eXtends.-; downwardly.- into. recess. 5 A, bevel" gear 14a is i mounted HPQHJShfifIQ 8 :andtisarigidly secured thereto. by means of) set! screw. 15. The! bevel} gear. 14rmeshestwithi a companion; gear; 1-6 which-t may be, freely rotatable. upom. the F shafta-13g the. arrangement? being: such that rotatiorp ofushaft: 8 2resu1tsinrotationeofi" the companion: bevelzgear 16:

A. container: 17, constructed oft-arr electrical insulating: material such. as-hard -rubber,;.plastic resinorrth'e like,- is. mounted upon thebottornportiorr of the housing;- 1 and forms a closure for recess 5;". A conicalflrecessa181is-provid'edi in, the outer portion of thecontamer. 1H 1 andis adapted to receive-the :conical. tip: oia seti screw 'l-9lwhich is threadedly positioned inthe centralportion of a U- shaped bracket-20. Arms 21 of the br acket- 20-carryscrews 221which: may engageopposite sides of the housing 1 to secure the container firmly in position upon the;

housin-g A metal ring or plate 23 is mounted uponthebottornof the' -container 1 7" and iselectrically connected toa jumper 24 which extends through the bottom of thecontainer; A- conductor: 2'5 connects the-jumper 24eto electrical instrumentality: 26 which', turn; may be connected to battery 27 or other source-of;electrie-power'by means of conductor-"28. The opposite;side-'ofijthepower source-27 maybeconnected to-th'e body of h'ousing l by means of conductor29. The device=-26- may comprise an electrical mechanismwvhose control may be relate'd to the rotation of shaft 8 or said' devicem-ay comprisqa relay; which may I indirectly control an operation or; give a'- signal in response; to a apredetermined 'r-otary speed Off shaft 8.

The gear 16 may comprise a depending disk-portion-30;

surfaceof disk- 30 andthefreeends thereof trail at anangle with respect -to-their fi xed ends, relative;- to the;

direction of; rotation of ,thegear 156- which moves in the direction of the -arrows; as shown-in F-igs.-- 1 and 2i When the gear 16 is stationary or rotates at a speed below a predetermined speed, the free ends of the blades 31 make contact with the upper face of the ring or plates 23, thereby completing the circuit to the device 26. However, when said speed is exceeded the circuit to the device 26 is broken by the deflecting force or thrust exerted upon the surface of the blade 31 by the liquid 33.

The critical speed at which the blades 31 break contact with the plate 23 may be controlled by selecting springs of desired resiliency, or increasing or decreasing the area of said blades particularly the portion thereof which contacts the liquid 33. The critical speed may also be controlled by the proper selection of viscosity of the liquid 33, which preferably comprises a non-conducting oil. Of course, by obvious means (not shown) the shaft may be coupled to any rotating or rectilinearly moving body the speed of which determines the action which is to be controlled by the signal 26. Thus, the shaft 8 may be rotated proportionately higher or lower than the critical driving device, that is, it may be geared upwardly or downwardly. Similarly, the gears 14 and 16 may be so related as to step up or step down the speed of the critical driving device and thus the control exercised by the device 26 may take place over a Wide variety of speeds.

To stabilize the rotation of the gear 16 and disk 30, a hollow boss 34 may extend upwardly from the bottom of the container 17 and a restricted end portion 35 of shaft 13 may extend thereinto for support. The gear 16 and disk 30 may be supported by the upper portion of the boss 34 or said gear and disk may be supported upon the spring blades 31.

Although three blades 31 are shown and described, it

r! u l t. r.

is to be Understood that one or more blades may be used. If a plurality of blades are employed they may all be connected in parallel, as shown or if desired each blade may be insulated from the disk 30 and may be connected by means of slip rings or the like (not shown) to separate circuits wherein the plate 23 will form a common return. In the latter case the spring blades may be of different resiliency, area, or weight wherein they may break their respective circuits at different speeds of the disk 30.

The free end portions of the blades 31 may be coated with mercury, as may also the upper surface of the plate 23, to secure better electrical contact between the blades and the plate, or, if desired, a pool of mercury (not shown) may be disposed immediately above the plate 23 and below the surface of the liquid 33 in which the blade ends may dip and with which the blades may break contact at a predetermined speed. The gear 16 and disk 30 preferably rotate in a horizontal plane, that is, about a vertical axis. However, it has been found that the entire device can be canted through a relatively small angle and yet it will function eificiently.

We claim as our invention:

1. An electric switch responsive to the rotary speed of a body which comprises, a container, an electrically conductive member carried in the container, an electrically non-conductive liquid carried in the container in contact with and above the conductive member, a rotary element positioned above said liquid, a resilient metal blade se cured at one end to the bottom of said rotary element with the free end thereof extending downwardly into said liquid and in resilient contact with said electrically conductive member when said rotary element is stationary, means for rotating said rotary element in timed relationship with the rotation of said body whereby said blade is resiliently deflected by the frictional force of said liquid thereon and breaks contact with said conductive member when said rotary element reaches a predetermined speed, and means for connecting the resilient blade and the electrically conductive member to opposite sides of an electrical circuit.

2. An electric switch responsive to the rotary speed of a body which comprises, a container constructed of insulating material, a metal plate carried in the container, a pool of electrically non-conductive liquid carried in the container in contact with and above the metal plate, a rotary element positioned above said liquid, a resilient metal blade secured at one end to the bottom of said rotary element with the free end thereof extending down-- wardly into said liquid and in resilient contact with said metal plate when said rotary element is stationary, means for rotating said rotary element in timed relationship with the rotation of said body whereby said blade is resiliently deflected by the frictional force of said liquid thereon and breaks contact with said metal plate when said rotary element reaches a predetermined speed, and means for connecting the resilient blade and the metal plate to opposite sides of an electrical circuit.

3. An electric switch responsive to the rotary speed of a body which comprises, a container, an electrically conductive member carried in the container, a pool of electrically non-conductive liquid carried in the container in contact with and above the conductive member, a rotary element positioned above said liquid, a resilient metal blade fixed at one end to the bottom of said rotary element with a free end portion thereof extending downwardly into said liquid and in resilient contact with said electrically conductive member when said rotary element is stationary, means for rotating said rotary element in timed relationship with the rotation of said body, said free end portion being disposed in trailing relationship to the fixed end portion thereof when said element rotates whereby said blade is resiliently deflected upwardly by said liquid and breaks contact with said conductive member when said rotary element reaches a predetermined speed, and means for connecting the resilient blade and the electrically conductive member to opposite sides of an electrical circuit.

4. An electric switch responsive to the rotary speed of a body which comprises, a container, an electrically conductive member carried in the container, a pool of electrically non-conductive liquid carried in the container in contact with and above the conductive member, a rotary element positioned above said liquid, a plurality of circumferentially spaced resilient metal blades each secured at one end to the bottom of said rotary element with the free ends thereof extending downwardly into said liquid and in resilient contact with said electrically conductive member when said rotary element is stationary, means for rotating said rotary element in timed relationship with the rotation of said body, whereby said blades are resiliently deflected by said liquid and break contact with said conductive member when said rotary element reaches a predetermined speed, and means for connecting the resilient blades and the electrically conductive member to opposite sides of an electrical circuit.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 726,125 Wetzel Apr. 21, 1903 2,109,732 Nielsen Mar. 1, 1938 2,518,478 Kohl Aug. 15, 1950 2,584,983 Butterworth Feb. 12, 1952 

